东海海樽类数量分布及与环境的关系

RELATIONSHIP OF WATER ENVIRONMENT AND ABUNDANCE DISTRIBUTION OF THALIACEA IN THE EAST CHINA SEA

提要根据1997—2000年东海23°30′—33°00′N、118°30′—128°00′E海域4个季节海洋调查资料,采用方差贡献和逐步回归分析方法探讨东海海樽类的数量变化和相应的动力学。结果表明,海樽类是东海浮游动物第二大类群,在数量上仅次于桡足类,其丰度春季最高,夏季次之,冬季最低;冬、春和夏季的东方双尾纽鳃樽(Thalia orientalis)和冬、秋季的小齿海樽(Doliolum denticulatum)是影响海樽类数量分布的主要优势种;海樽类高丰度区常位于暖流与各水团交汇处的偏暖流一侧,其数量变化的动力主要来自暖流势力的消长。海樽类在东海出现率较低,集群性强,较高丰度的分布仅局限在暖流势力范围内,其高丰度水域是东海暖流锋面的一个重要标志。

To find out the relationship of Thaliacea in water mass and fishing ground in the East China Sea, dynamic change in abundance of Thaliacea in the East China Sea was studied statistically based on 4 seasonal investigation data obtained in area of 23° 30＇-33° 00＇N/118° 30＇-128° 00＇E between 1997 to 2000. The result showed that Thaliacea, ranking next to copepods in quantity, was the second largest zooplankton group, with maximum in spring, minimum in winter, and summer-autumn in between. Two species, Thalia orientalis in spring and summer, and Doliolum denticulatum in autumn and winter, were shown to be dominant in abundance distribu- tion. Stepwise regression showed no clear relationship of the autumn abundance and total abundance to hydrological factors, whereas the spring abundance clearly related to bottom salinity and 10m-salinity; the summer abundance to surface-salinity and bottom-temperature; and the winter abundance to 10m-temperature. High abundance mainly occurred by a warm current to which all water masses converged. The dynamic change in the abundance was mainly forced by warm currents in the area. Thaliacea was an important indicative species for having low concurrency, high aggregation, and special distribution in warm current area with high abundance, which is a good indicator of the front of a warm current. The results will help understand Thaliacea biology and ecology in the sea.